Relationships Between Gas-Phase Film Deposition, Properties and Structures of Thin SiO[sub 2] and BPSG Films

Abstract

This paper is devoted to the analysis of relationships between chemical vapor deposition ͑CVD͒ features and silicon dioxide and silicate glass film properties and structures. Deposition processes have been quantitatively characterized using an empirical parameter the effective constant of the deposition rate, K eff . The observed CVD kinetic features are explained by using a simplified multiroute and multistep kinetic scheme of the silicon-based thin-film gas-phase deposition processes, and a classification of the studied processes. The basic physical and chemical properties of thin glass films are explained in terms of the glass structural disordering, which defines the oxide film density, wet etch rate, shrinkage, and intensity of film-moisture interaction. The structure disordering depends in reverse order with respect to K eff . It is shown that the borophosphosilicate glass ͑BPSG͒ film structure and properties are affected by the quantity of boron atoms with a threefold coordination with respect to the oxygen atoms. The boron coordination in BPSG film tends to change from threefold to fourfold coordination along with the increase of phosphorus to boron ratio in the film. The best BPSG structural ordering and the best film properties correspond to the boron concentrations defined by an empirical equation ͓B͔ р 0.4͓P͔. The respective glass film structure is supposed to consist of SiO 4 , PO 4 , and BO 4 tetrahedra.Thin films of silicon dioxide and phosphosilicate glass ͑PSG͒, borosilicate glass ͑BSG͒ and borophosphosilicate glass ͑BPSG͒ are used in Ultralarge-Scale integrated ͑ULSI͒ circuit technology for shallow trench isolation, spacer isolation, premetal and intermetal dielectric isolation, final device passivation, etc. These dielectric films are deposited using a variety of precursor combinations and gas-phase deposition methods, such as atmospheric, subatmospheric, or low-pressure chemical vapor deposition ͑APCVD, SACVD, and LPCVD, accordingly͒, plasma-enhanced deposition ͑PECVD͒, high-density plasma deposition ͑HDP-CVD͒, etc. Despite a number of published papers regarding thin-film deposition processes and film properties, just a few technologically oriented attempts have been made in order to summarize the accumulated experimental data. 1-6 These reviews cannot be considered to be sufficient enough; for instance, until recently there are no summaries devoted to the correlation of film properties and film structures with gas-phase deposition features. In this paper, an attempt is made to consolidate our previously published data 5-30 in order to define these relationships. Cited papers have been focused on the investigation of SiO 2 , PSG, BSG, and BPSG films deposition kinetics, 7-12 BPSG films flow properties, 11,13-18 PSG and BPSG moisture absorption effects, 11,19-24 BPSG defect formation phenomenon, 11,25 glass film electrical properties, 26,27 PSG and BPSG gap-fill issues, 9,11,12,[20][21][22][23][28][29][30] and quantitative optimization of BPSG film composition. 11,15,16 Chemical bonding and str...

Evaluation of Low Temperature TEOS-Ozone Silicon Dioxide Thin Film CVD under Sub-Atmospheric Pressure Using Consecutively Pulsed Reactant Injection

“…However, the addition of boron-, and/or phosphorus compounds to deposit glass thin films causes changes in the reaction scheme and shift the reaction into the gas phase. [19][20][21] This changes the film properties significantly, worsening the film step coverage and gap-filling capability. Summary of all these features can be found in the author publications.…”

“…This made TEOS-ozone CVD process applicable for new generations of IC devices, basically due to urgent gap-filling needs of sub-quarter micron IC technology. A few lowtemperature thermally-activated IC production tools and CVD processes for thin films of silicon dioxide, phosphosilicate and borophosphosilicate glasses were studied and developed in a mid of 1990 th , [15][16][17][18][19][20] see also summary in the author's summary 21 and a monograph. 22 Unique features of TEOS-ozone CVD processes for silicon dioxide (frequently called also "undoped silicate glass", USG) were described in details in.…”

“…This evaluation idea is based on the assumption that surface reactions play important role in the TEOS-ozone interaction at CVD processes. [20][21][22][24][25][26] Notes: -ozone concentration shown for the oxygen flow 5000 sccm; -parameters highlighted by (*) were the pulsed recipes variables.…”

Review—Mechanical Stress in Chemically Vapor Phase Deposited Boron- and Phosphorus-Contained Silicate Glass Thin Films: A Review

“…This means it should demonstrate lower film density (or vice versa: higher film porosity) and higher film shrinkage as compared to the perfect material, such as thermally grown silicon dioxide. Analysis of silicon dioxide and glass thin film CVD kinetics considered earlier 47,67 allows concluding that APCVD/SACVD processes are performed at significantly deeper chemical reaction time as compared to LPCVD/ PECVD processes. The consequence of this kinetic feature is an ability to form reaction products in the reaction gas-phase in a form of microscopic particles, embedded in the growing films.…”

Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition of Borophosphosilicate Glass Films

“…Generally, the dielectric films are deposited by a various of CVD methods, such as atmospheric pressure CVD (APCVD), sub-atmospheric CVD (SACVD), low-pressure CVD (LPCVD), and plasma enhanced CVD (PECVD). 2,3) These CVD methods have different characteristics and special applications: APCVD allows high throughput and even continuous operation, SACVD and LPCVD provide superior conformal step coverage and better film homogeneity, and PECVD, in which low temperatures are required, has been conventionally used. 4) Recently, considerable attention has been paid to atmospheric pressure plasma enhanced chemical vapor deposition.…”